I think you've hit the nail right on the head.
Goodes dared to comment, speak up, act and even criticise although with balance.
The reason other indigenous players do not get booed is that they don't speak up. Although you can bet Lewis Jetta has a target on his back with West Coast fans.
The events are clear:
Despite racial vilification laws and AFL laws regarding racist comments or behaviour, Goodes dared to point out a comment in the MCG crowd in 2013 (how many others he could not pinpoint before that you have to wonder) . It turned out to be a 13 year old girl, who knew exactly what she was saying. A lot of the hidden racists hated that he did that.
This bubbled to the surface with his AOTY appointment in 2014. His speech adding more grist to the racist mill.
Then the booing started and it has really taken off in 2015, culminating with the indigenous round where Cartlon fans did booed him, so after months of copping it, he planned to give them the war dance. It was symbolic, an act of defiance against the hate and ignorance.
The booers can't stand a black man standing up for himself so the crescendo of boos has reached fever pitch ever since, Hawthorn game and West Coast in particular.
And now, after months, years of putting up with being considered less than human, he has been booed off the sporting field.
But many aren't happy even with that, they want to blame Goodes for it all and tell him to toughen up.
FFS - for those who make excuses for the boos and blame Goodes you are failing to think. This is not the popular view and there are plenty of folks willing to grind Goodes and make the booers feel better about themselves. Let's see, Akermanis, Brereton, Bolt, Sam Newman, Warne, Paniha, et al.
Are people that insecure that they can't reflect and see what this is all about?

Politicians perceiving the jeering becuase of their political views is something they would expect. It is much more personal when it is about how you look or the implication is that you are less than human.
Walk the walk then you might be able to talk to talk.

Yeah worth a shot, but no.
Carey, Brereton et al embraced their villain status but they did not carry around any stigma other than being a champion player who could stick it up opposition fans. Goodes burden is much more deep and serious in nature to make a mockery of it.